Computers running slow can be caused by a lot of things; your CPU is average but adequate for most things other than gaming and video editing.
One of the major causes of slow PCs is that there is too many programs running at startup.
If you look on the bottom right of the screen, you can see what programs load automatically and most of these can be disabled, running only when you need them.
Many can be disabled as follows:
click the startup tab and see what is listed there. Leave your antivirus / firewall ticked but untick the others. Post a list here if you wish and you can be told what to disable.
click here for a good listing.